Those are great suggestions.
We've looked into what it would take to "undo" an action, and because of the complications of dice rolls forcing some actions to be locked in, we added confirmations for most of those actions in place of "undo".

Known issues in the current build (1.2.2):
Lash's Gift sometimes gets stuck when prompting to discard a card.
STATUS: Fixed in the next build. Workaround: don't set the animation speed to max - stop a little below max.
Kincaid and Mortimer's stunt cards may sometimes cause target cards to land in the wrong location.
STATUS: Fixed in the next build. It turns out this was the same animation speed bug as the problem with Lash's Gift.
Bug reports don't submit correctly from the tutorial
STATUS: Fixed for the next build.
Online games created on Amazon devices fail to start correctly.
STATUS: Fixed for the next build.
Using Winter Knight Harry's Investigate card, "The Za Lord's Guard" in Storm Front causing a sequence that solves "Victor Is Missing", solves "Who is the Shadowman?" from the effect of "Victor Is Missing" with "Who is the Shadowman?" in the row following "Victor is Missing" causes the game to get stuck.
STATUS: Fixed for the next build.
Selecting Winter Knight Harry's stunt while playing Ghost Train and then canceling the stunt use ends up moving the Soul Train card forward
STATUS: Fixed for the next build.
Solving Hit on the Carpenters in a Side Jobs game when there are no other cards in the row causes the game to get stuck.
STATUS: Fixed for the next build.
*Aristedes is not correctly taking damage from attack cards that also damage adjacent targets, like Winter Lady Molly's Illusory Betrayal.
STATUS: Fixed for the next build.